The present invention relates to maritime transportation of cargo and, more particularly, to a cargo lashing fitting affixed to the deck of a vessel for the securing of cargo.
Transportation of cargo requires securing systems which include devices that ensure that such cargo remains safely stowed and stationary during transit. In this regard, the deck(s) of the transportation vehicles, e.g., ship, railcar, etc., typically include a plurality of cargo lashing fittings, often referred to as sockets or socket assemblies.
The maritime transportation of cargo requires securing systems which include devices that can support and transfer the very high loads experienced as a result of the ship's dynamics and environmental conditions. These high loads often dictate that the socket assembly fixture affixed to the vessel be made of properly designed and treated steel.
As ships are being designed to be lighter, faster and more economical, aluminum alloy structure is becoming more common, including for large commercial and military vessels. This usage of aluminum alloy for the deck increases the difficulty of designing and installing a socket that will handle and properly transfer loads to the ship's structure. First, the socket must be compatible with the aluminum alloy deck of the ship. Second, aluminum alloy is susceptible to galling from the hook of the lashing gear, thereby resulting in wear of the lashing fixture of the socket.
In addition, prior art sockets are typically installed as an integrated unit. This means that if the lashing fixture is damaged and/or worn, the entire socket must be “cut” out of the deck of the ship. This is, of course, a time consuming, intricate, and costly procedure. There may also be applications where the preferred lashing fixture (e.g., cloverleaf vs. crossbar vs. other) varies depending on the nature of the application.
Attempts have been made to provide a socket having a removable/replaceable lashing fixture. However, these prior art sockets typically require a plurality of fasteners that must be removed for extraction. In addition, these prior art sockets require fastener removal/installation tools and extended time to complete the removal/replacement.
There is therefore a need in the art for a socket which is adapted for installation in an aluminum deck of a vessel, and which provides a lashing fixture which may be removed/replaced without flame cutting of the entire socket from the aluminum deck. There is a further need in the art for a socket which provides a lashing fixture which may be removed/replaced in a shortened time period and without the use of tools.